Measurement Of The Laser Target Angular Vibration

Laser measurement technology is a measurement technique with the absence of injury and high in precision and efficiency. Due to its long-range, non-contact measurement, it has been widely used in the measurement of slight vibration, velocity and tiny deformation of the target. Compared with other laser measurement technology, the digital speckle correlation can realize non-contact measurement, full field measurement. Besides, it has other advantages, such as simple optical path, low demand of measurement circumstance, without the process of dealing with the interference fringes as well as photographic developing and fixing, achieving the real-time measurement, simple in operation and so on. The technology has been widely used in the measurement of plane displacement, surface displacement and the particles movement. Based on digital speckle correlation method and FPGA, a program to measure the angular vibration of the target has been proposed, and a measurement system with advantages like real-time, fast, dynamic measurement, low cost and simple structure has been built in this dissertation. At last, the angular vibration of the target has been studied using this measurement system.The main contents of this dissertation have been summarized as follows:1. The basic theory of digital speckle correlation method (DSCM) was elaborated, and several methods of relevant search were described.2. The design scheme of the measurement system was given, and the working principle of the system, work flow, and the generation mechanism of the speckle image were described. Because of the high price of the high-speed area CCD-array and the low rate of the processing of traditional digital speckle correlation method, the linear CCD and FPGA processing system were selected to make the measurement system to achieve the purpose of real-time, fast, dynamic measurement at a low cost.3. The hardware design and implementation of the measurement system were elaborated. The selection of all the devices, the design of system power, FPGA configuration circuit, CCD drive circuit, signal conditioning circuit and A/D converter circuit were detailed.4. The logic design using the Verilog-HDL language and implementation of the measurement system were described, including the CCD driven timing, storage and computing of the speckle images and the output of the results.5. An experimental platform to measure the angular vibration of target was built. The feasibility of the measurement system was verified by the reduction of speckle images. Using the measurement system, the vibration of the speaker driven by the signal generator was measured, and the trajectory, amplitude and frequency information of the speaker’s angular vibration were got.